Skeletal structure

ABSTRACT

A skeletal structure is provided that includes a panel, and a frame joined to a front surface side of the panel. The frame includes a plurality of first frames oriented in a fixed direction and a second frame oriented in a direction orthogonal to the plurality of first frames, and each of the plurality of first frames and the second frame are formed to have an open cross-sectional shape. An end portion of each first frame of the plurality of first frames is joined to the second frame in an overlapping state.

This is a Continuation of U.S. application Ser. No. 16/711,651 filed onDec. 12, 2019, now U.S. Pat. No. 11,046,221, which is a Continuation ofU.S. application Ser. No. 15/771,959 filed on Apr. 27, 2018, now U.S.Pat. No. 10,576,858, which in turn is a PCT National Phase Applicationof PCT/JP2016/081269 filed on Oct. 21, 2016, which claims priority to JP2015-212534 filed on Oct. 29, 2015, JP 2015-212537 filed on Oct. 29,2015, and JP 2015-212538 filed on Oct. 29, 2015. The disclosure of theprior applications is hereby incorporated by reference herein in itsentirety.

TECHNICAL FIELD

The present invention relates to a skeletal structure including a paneland a frame.

BACKGROUND ART

Each of Patent Literatures 1 to 4 discloses a skeletal structure used ina backrest of a rear seat of a vehicle seat.

Each of these skeletal structures includes a panel formed of asubstantially rectangular metal plate and a frame joined and mounted onthe panel. The frame is formed of a pipe material provided along anouter edge of the panel.

The region without the frame on the panel of the skeletal structureincludes a plurality of beads formed of metal plate bulging into ridgeshapes and is reinforced by the beads.

PRIOR ART DOCUMENT Patent Documents

-   Patent Literature 1: Japanese Patent No. 4859195-   Patent Literature 2: Japanese Patent No. 5526718-   Patent Literature 3: Japanese Patent No. 5526719-   Patent Literature 4: Japanese Patent No. 5544837

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention

It is desirable that the skeletal structure with a panel has highrigidity to suppress deformation even in a case where an object collidesagainst the panel. It would be difficult, however, to achieve highrigidity by increasing the plate thickness because of demands for aweight reduction in the skeletal structure.

For this reason, recently there has been proposed a skeletal structuredesigned on the presupposition that deformation of the panel isgenerated at the time of collision against an object and capable ofabsorbing collision energy by deformation so as to reduce destruction ofthe skeletal structure as much as possible.

Ina case, however, where the central portion of the panel is deformed bycollision against an object in the skeletal structure using panels suchas the skeletal structures described in Patent Literatures 1 to 4, thedeformation amount might be maximized to cause breakage in some cases.

This needs countermeasures such as suppression of deformation in a zonehaving possibility of receiving large-scale destruction, or deliberatelydeforming the zone unlikely to develop large-scale destruction. However,consideration for such countermeasures is not found in the skeletalstructures described in Patent Literatures 1 to 4.

Therefore, it is an object of the present invention to enablecontrolling deformation of the skeletal structure.

In addition, conventionally used round pipe materials for the frame hada problem of difficulty in securing sufficient contact area in joiningframes with each other due to their original shapes. This led to apossibility of insufficient joining strength in welding, or the like.

Moreover, due to the difficulty in securing sufficient contact area,there is a need to perform welding or the like using welding materialthat fills a gap for joining, leading to limitation in implementing ajoining method.

Therefore, another object of the present invention is to enhance thejoining strength of the frame of the skeletal structure.

Meanwhile, reinforcement is conventionally performed by forming anirregular structure formed with a plurality of beads on a panel.However, sufficient strength could not be ensured merely by forming thebeads.

For example, application of the skeletal structure to the structure of abackrest of a rear seat includes a case where the backrest of the rearseat is folded forward so as to accommodate a load mounted thereon. Insuch a case, the conventional skeletal structure sometimes remains in adeflected state with stress. Returning the backrest to its originalposture after removing the baggage would then cause the skeletalstructure released from the load of the baggage to recover from thedeformed state to generate a large abnormal noise in some cases.

In view of the above, another object of the present invention is toenhance the strength of the skeletal structure.

Means for Solving the Problem

In order to achieve the above object, the invention according to claim 1is characterized in a skeletal structure including: a panel; and a framewhich is joined to a front surface side of the panel, wherein the frameincludes a plurality of first frames oriented in a fixed direction and asecond frame oriented in a direction orthogonal to the first frame, thefirst frame and the second frame are formed to have an opencross-sectional shape, each of the first frame and the second frameincludes an opposing wall facing the panel and a pair of side wallsrising from both side portions of the opposing wall toward the panel,the plurality of first frames includes joint portions and non-jointportions to the panel along a longitudinal direction of the firstframes, and the non-joint portions of all the first frames are arrangedat positions matching or overlapping with each other with respect to thelongitudinal direction of the first frames.

The invention according to claim 2 is characterized in the skeletalstructure according to claim 1, wherein the non-joint portions of allthe first frames are present on one side with respect to a centralportion in the longitudinal direction of the first frames.

The invention according to claim 3 is characterized in the skeletalstructure according to claim 2, wherein the non-joint portions of thefirst frames at both end portions in an arrangement direction of theplurality of first frames are present at positions closer to the centralportion in the longitudinal direction of the first frames with respectto the non-joint portion of the first frame at a central portion in thearrangement direction.

The invention according to claim 4 is characterized in the skeletalstructure according to any one of claims 1 to 3, wherein a plurality ofreinforcing structure sections surrounded by a bead bulging into a ridgeshape is formed on the panel.

The invention according to claim 5 is characterized in the skeletalstructure according to claim 4, wherein the plurality of reinforcingstructure sections is formed along the longitudinal direction of thefirst frames, and the non-joint portion of the first frame is present ina range including one or more boundaries between the reinforcingstructure sections in the longitudinal direction of the first frames.

The invention according to claim 6 is characterized in the skeletalstructure according to any one of claims 1 to 5, wherein the first frameand the second frame located at a corner of the panel are coupled witheach other via a plate-like set bracket equipped with a projection nut.

The invention according to claim 7 is characterized in the skeletalstructure according to any one of claims 1 to 6, wherein the panel andthe frame are joined to each other on mutual joint surfaces by asolidified state after melting generated in the panel and the frame.

The invention according to claim 8 is characterized in the skeletalstructure according to any one of claims 1 to 7, wherein an end portionof the first frame is joined to the second frame in an overlappingstate.

Effects of the Invention

According to the invention of claim 1, since non-joint portions of allof first frames are arranged to match or overlap with each other withrespect to the longitudinal direction of the first frame, in a casewhere a collision load or a deformation load is applied to the skeletalstructure, it is possible to perform control so as to generatedeformation in the matching or overlapping position of the non-jointportions in the longitudinal direction of the first frame.

This configuration enables generating deformation at a position otherthan a position that would receive a large deformation amount at theoccurrence of deformation, making it possible to reduce the deformationamount.

According to the invention of claim 2, since the non-joint portions ofall the first frames are present on one side with respect to a centralportion in the longitudinal direction of the first frames, it ispossible to generate deformation at a position other than the centralportion that receives the large deformation amount at the occurrence ofdeformation, making it possible to reduce the deformation amount.

According to the invention of claim 3, the non-joint portions of thefirst frames at both end portions are arranged at positions closer to acentral portion in the longitudinal direction of the first frames withrespect to the non-joint portion of the first frame at the centralportion. With this configuration, even when a collision load or adeformation load is applied to the center of the panel, it is possibleto generate deformation along an arc along which the non-joint portionsare arranged. This makes it possible to more effectively guide adeformation position and to reduce the deformation amount.

According to the invention of claim 4, since a plurality reinforcingstructure sections surrounded by beads is provided, it is possible toreceive the load applied to the skeletal structure for each of thesections and suppress the overall deformation.

In addition, arranging the plurality of sections makes it possible toreduce the planar deflection and elastic deformation of the panel,leading to the reduction of the occurrence of abnormal noise due toreturn from the deformed state.

According to the invention of claim 5, the non-joint portion of thefirst frame is present in a range including one or more boundariesbetween mutual reinforcing structure sections in a longitudinaldirection of the first frame. This configuration provides the non-jointportion in the range including the boundary between the mutualreinforcing structure sections likely to have deformation, and it ispossible to control the deformation position further effectively andreduce the deformation amount.

According to the invention of claim 6, the first frame and the secondframe located at a corner of the panel are coupled with each other via aset bracket. This makes it possible to couple the first frame with thesecond frame without causing interference with a projection nut providedon the set bracket and without adding a special structure to avoidinterference.

According to the invention of claim 7, since the panel and the frame arejoined to each other at mutual joint surfaces by a solidified stateafter melting generated in the panel and the frame. With thisconfiguration, it is possible to provide a skeletal structure that islightweight while maintaining high joining strength without a weldingmaterial.

According to the invention of claim 8, since an end portion of the firstframe is joined to the second frame in an overlapping state, it is easyto ensure a wide area of the joint, making it possible to enhance thejoining strength.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 This is a front view of a skeletal structure of a vehicle seataccording to a first embodiment.

FIG. 2 This is a perspective view of a skeletal structure of a vehicleseat.

FIG. 3 This is a left side view of a skeletal structure of a vehicleseat.

FIG. 4 This is an enlarged front view illustrating three sections beingextracted.

FIG. 5 This is a perspective view of a joint between an upper frame anda middle frame.

FIG. 6 This is an enlarged perspective view of the joint of FIG. 5 .

FIG. 7 This is a front view of a skeletal structure illustrating a jointof a side frame and a middle frame with respect to a panel illustratedin a pattern.

FIG. 8 This is a front view of a joint between an upper frame and amiddle frame.

FIG. 9 This is a perspective view of a joint between an upper frame anda middle frame viewed diagonally from the front upper side.

FIG. 10 This is a perspective view of a cross section taken along lineX-X of FIG. 8 as viewed diagonally from the left front upper side.

FIG. 11 This is a perspective view of a cross section taken along lineY-Y of FIG. 8 as viewed diagonally from the right front upper side.

FIG. 12 This is a perspective view illustrating a portion of a left-sidearmrest bracket in a vertical section.

FIG. 13 This is a perspective view illustrating a portion of a left-sidearmrest bracket in a horizontal section.

FIG. 14 This is a front view of a skeletal structure of a vehicle seataccording to a second embodiment.

FIG. 15 This is an enlarged perspective view of an upper central portionof the skeletal structure of FIG. 14 .

FIG. 16 This is an enlarged perspective view of a lower left portion ofthe skeletal structure of FIG. 14 .

EMBODIMENTS FOR CARRYING OUT THE INVENTION Outline of First Embodiment

Hereinafter, a first embodiment of the present invention will bedescribed with reference to the drawings. While various technicallypreferable limitations for implementing the present invention areattached to the following embodiments, the scope of the presentinvention is not limited to the following embodiments and illustrativeexamples.

FIGS. 1, 2, and 3 are a front view, a perspective view, and a left sideview of a skeletal structure 100 of a vehicle seat, respectively. Thisvehicle seat is a rear seat of a plurality of passengers, and thisskeletal structure (frame structure) 100 is to be a framework of thebackrest of the rear seat. The skeletal structure 100 includes a foamedpad provided so as to enclose the skeletal structure 100 from the frontside of the skeletal structure 100, and an external skin is furthersuspended on the surface of the skeletal structure 100. Being suspendedis a state of the external skin covering the surface of the padstretched along the surface of the pad.

The skeletal structure 100 includes a panel 1, a frame 6, a striker 11,a plurality of headrest support members 12, a pair of armrest brackets13 and 14.

The panel 1 has a substantially rectangular shape and is a metal plateformed of steel, an aluminum alloy, or the like. As illustrated in FIG.1 , the panel 1 is mounted on a vehicle seat in a state where adirection along the long side of the panel 1 comes along a lateral(left-right) direction and a direction along the short side comes alonga vertical (up-down) direction.

In a state where the skeletal structure 100 is mounted on the vehicleseat, the left side of the vehicle is defined as the left side of theskeletal structure 100 and the right side of the vehicle is defined asthe right side of the skeletal structure 100. In FIG. 1 , the front sideof the page is defined as the “front” and the back side of the page isdefined as the “rear”.

[Outline of Frame]

As illustrated in FIGS. 1 to 3 , the frame 6 includes: side frames 61and 61 as first frames attached on the left and right end portions ofthe front surface of the panel 1, respectively, along the up-downdirection; middle frames 62 and 62 as first frames attached on the frontsurface of the panel 1 along the up-down direction at a portion slightlycloser to the central portion from the left and right end portions; anupper frame 63 as a second frame attached on an upper end portion on thefront side of the panel 1 along the left-right direction; and a lowerframe 64 as a second frame provided at the lower end portion of thefront side of the panel 1 along the left-right direction.

Each of the frames 61 to 64 is a metal support column formed of steel,aluminum alloy, or the like.

The upper end portions of the side frames 61 and 61 and the middleframes 62 and 62 are joined to the upper frame 63 by laser welding. Thelower end portions of the side frames 61 and 61 and the middle frames 62and 62 are joined to the lower frame 64 by laser welding.

All the frames 61 to 64 have flange portions opposed to the panel 1, andthe flange portions are joined to the panel 1 by laser welding.

Detailed structures of these frames 61 to 64 will be described below.

[Outline of Panel]

As illustrated in FIGS. 1 and 2 , the panel (pan frame) 1 is arectangular plate-shaped metal plate elongated in the left-rightdirection, and its upper portion is slightly widened.

Additionally, an edge formed by a forwardly raised entire outerperiphery of the front surface of the panel (pan frame) 1 is provided toform a tray-like shape.

Furthermore, groove-shaped recesses 21 and 22 recessed rearward arerespectively formed in the upper end portion and the lower end portionof the front surface of the panel 1 along the left-right direction. Theupper frame 63 of the frame 6 is provided inside the upper recess 21 andthe lower frame 64 is provided at the lower recess 22.

The portion between the upper and lower recesses 21 and 22 on the frontsurface of the panel 1 is divided into three regions by the left andright side frames 61 and 61 and the left and right middle frames 62 and62. That is, the front surface of the panel 1 is divided into threeregions, namely, a left region A between the left-side side frame 61 andthe left-side middle frame 62, a right region B between the right-sideside frame 61 and the right-side middle frame 62, and a central region Cbetween the left-side middle frame 62 and the right-side middle frame62.

[Panel: Left Region]

The left region A of the panel 1 includes reinforcing structure sections30A, 30B, and 30C formed to be arranged vertically. That is, thesections 30A, 30B, 30A, 30B, 30A, and 30C are arranged in order from thetop.

FIG. 4 is an enlarged front view of extracted upper three sections 30A,30B, and 30A.

As illustrated in FIG. 4 , the reinforcing structure section 30Aincludes four beads 31 to 34 surrounding the section 30A and auxiliarybeads 35 to 39 dividing the section 30A surrounded by the four beads 31to 34 into subsections 41 to 45.

The bead is a ridge-shaped (rail-like) structure formed so as to bulgeforward from the front surface of the panel 1 (this similarly applies tothe auxiliary bead). In a case where a flat metal plate is used to formthe panel, winding or bending would be likely to occur on its flatsurface. Instead of this, forming ridge-shaped beads by plastic working,however, it is possible to enhance the rigidity to prevent bending ofthe beads.

The reinforcing structure section 30A has a rectangular shape, foursides of the rectangle are formed with the beads 31 and 33 along theleft-right direction and the beads 32 and 34 along the up-downdirection. Adjacent beads forming a corner are linked with each other byan arc-shaped bead.

On the inner side of the rectangular section 30A surrounded by the fourbeads 31 to 34, four auxiliary beads 35 to 38 connected in a zigzagmanner in the left-right direction and auxiliary bead 39 formed in theup-down direction at the central portion in the left-right direction areprovided.

In a lower right portion of the section 30A, a right triangulartruss-shaped subsection 41 is formed, surrounded by the beads 33, 34 andthe auxiliary bead 35.

In addition, in the lower central portion of the section 30A, atruss-shaped subsection 42 of an isosceles triangle shape is formed,surrounded by the bead 33 and the auxiliary beads 36 and 37.

In a lower left portion of the section 30A, a right triangulartruss-shaped subsection 43 is formed, surrounded by the beads 32 and 33and the auxiliary bead 38.

In addition, in the upper right portion of the section 30A, atruss-shaped subsection 44 of a substantially triangle shape is formed,surrounded by the bead 31 and the auxiliary beads 35, 36, and 39.

In addition, in the upper left portion of the section 30A, atruss-shaped subsection 45 of a substantially triangle shape is formed,surrounded by the bead 31 and the auxiliary beads 37, 38, and 39.

The reinforcing structure section 30A formed with the beads 31 to 34 andthe auxiliary beads 35 to 39 is bilaterally symmetrical.

The reinforcing structure section 30B has a pattern shape formed withthe plurality of beads and the plurality of auxiliary beads beingvertically inverted pattern shape of the section 30A. That is, thesection 30B has a line-symmetrical pattern shape about a boundary linewith the adjacent section 30A along the left-right direction, as acenter.

As described above, since the shape and arrangement of the four beads,five auxiliary beads and four subsections of the section 30B areline-symmetrical with the section 30A, a detailed description thereofwill be omitted.

The reinforcing structure section 30C has a pattern shape formed with aplurality of beads and a plurality of auxiliary beads being similar tothe pattern shape of the section 30B.

This section 30C is located at the lowermost side within the region A,and thus, in order to avoid interference with a set bracket 16A mountedat a lower left corner of the panel 1, the left-side bead among the fourbeads on the outer periphery of the section 30C is formed to be inclinedso as to form the outer shape of the section 30C in a trapezoidal shape.

Except for the outer shape being in the trapezoidal shape, the section30C has almost the same structure as the section 30B, and thus adetailed explanation will be omitted.

The subsections 44 and 45 of the section 30A located at the upper endportion of the region A include through holes 46 and 47, respectively,formed to penetrate the panel 1 in a front-rear direction.

These through holes 46 and 47 are used for positioning the panel 1 withrespect to the laser welding apparatus in joining individual members tothe panel 1.

Moreover, in order to position the orientation of the panel 1 withhigher accuracy, similar through holes 48 and 49 are separately formedin the two subsections in a section 30D (described below) located at thelower end portion of the region C of the panel 1.

Note that the number of through holes is not limited to four, and it issufficient to have at least two through holes. In a case where twothrough holes are provided, it is desirable to form one each at thediagonal of the panel 1.

Alternatively, it is also allowable to provide four or more throughholes to reduce the weight of the panel 1 (for example, providing thehole for each of the sections).

[Panel: Right Region]

The right region B of the panel 1 includes reinforcing structuresections 30A, 30B, and 30D formed to be arranged vertically asillustrated in FIG. 1 . That is, the sections 30A, 30B, 30A, 30B, 30A,and 30D are arranged in order from the top.

The sections 30A and 30B are the same as the sections 30A and 30B of thereinforcing structure formed in the left region A described above.

Moreover, the section 30D has a pattern shape formed with the pluralityof beads and the plurality of auxiliary beads being horizontallyinverted pattern shape of the section 30C, that is, a line-symmetricalpattern shape with respect to the section 30C about an axis along anup-down direction as a center. In this manner, since the shape andarrangement of the four beads, five auxiliary beads and four subsectionsof the section 30D are line-symmetrical with the section 30C, a detaileddescription thereof will be omitted.

[Panel: Central Region]

The central region C of the panel 1 includes reinforcing structuresections 50A and 50B formed to be arranged vertically as illustrated inFIG. 1 . That is, the section 50A is formed at the upper end portion,and five sections 50B are formed to be arranged under the section 50A.

The reinforcing structure section 50B includes four beads surroundingthe section 50B and six auxiliary beads dividing the section 50Bsurrounded by the four beads into subsections.

The four beads form four sides of a rectangle similarly to theabove-described section 30A, with its corner having an arc shape likethe section 30A.

Each of the six auxiliary beads is arranged along the up-down directionat uniform intervals in the left-right direction between two beads alongthe left-right direction.

This results in arrangement of seven rectangular subsections having thesame rectangular shape formed side by side in the left-right directionin the section 50B.

While the reinforcing structure section 50A is different from thesection 50B in that the upper half of the beads on both the left andright sides are wider, the other configuration is the same, and thus,the detailed description will be omitted.

[Detailed Structure of Frame]

FIG. 5 is a perspective view of a joint between the upper frame 63 andthe middle frame 62, and FIG. 6 is an enlarged perspective view of thejoint.

As illustrated in the drawing, the upper frame 63 has an opencross-sectional shape and includes an opposing wall 631 opposed to thepanel 1 and a pair of side walls 632 and 632 rising from both sideportions of the opposing wall 631 toward the panel 1, and flangeportions 633 and 633 extending outward in the width direction from theend portion of the pair of side walls 632 and 632 on the panel 1 side.

Similarly, other frames constituting the frame 6, namely, the sideframes 61 and 61, the middle frames 62 and 62, and the lower frame 64have similar open cross-sectional shapes, and include opposing wall, apair of side walls, and the flange portion.

All of the frames constituting the frame 6 are joined in a state wherethe flange portion is in surface contact with the front surface of thepanel 1.

FIG. 7 is a front view of the skeletal structure 100 in which hatchedpatterns are attached to joints (laser welding spots) on the flangeportions 613 and 623 of the side frames 61 and 61 and the middle frames62 and 62 with the panel 1.

The flange portions 613 and 623 on each of the left and right sideframes 61 and 61 and the left and right middle frames 62 and 62,respectively, are joined by laser welding. That is, each of the flangeportions 613 and 623 is joined due to a solidified state after meltingthat occurs in the material for forming the flange portions 613 and 623and the material for forming the panel 1.

Each of the left and right side frames 61 and 61 and the left and rightmiddle frames 62 and 62 includes a joint portion s and a non-jointportion n with respect to the panel 1 along the longitudinal direction.Meanwhile, the left and right side frames 61 and 61 and the left andright middle frames 62 and 62 are joined by laser welding, and thus,there is a need to hold the flange portions 613 and 623 at regularintervals by jigs so as not to generate a gap at a contact surfacebetween the flange portions 613 and 623 and the panel 1. Accordingly,there is a discontinuity of welding due to the attachment of the jigswithin the range of the joint portion s. The non-joint portion n,however, does not represent this discontinuity inevitably generated inwelding, but represents a region where welding is not performed in arange of a certain length or more.

As illustrated in FIG. 7 , the ranges of the non-joint portions n in theup-down direction in the two side frames 61 and 61 match with eachother, and these ranges do not include middle positions in the up-downdirections of the side frames 61 and 61, and are located below themiddle positions.

Moreover, the ranges of the non-joint portions n in the up-downdirection in the two middle frames 62 and 62 also match with each other,and these ranges do not include the positions as the central portions inthe up-down directions of the middle frames 62 and 62, and are locatedbelow the middle positions.

In addition, while the non-joint portion n of the side frame 61 and thenon-joint portion n of the middle frame 62 overlap each other in anoverlapping range j in the up-down direction, the non-joint portion n ofthe side frame 61 is located above the non-joint portion n of the middleframe 62.

As described above, by providing the non-joint portion n on the left andright side frames 61 and 61 and the left and right middle frames 62 and62, it is possible to control a plastic deformation portion generated ina case where a load such as collision is applied to the skeletalstructure 100. That is, in the case of a flat plate-shaped structuresuch as the skeletal structure 100, deformation occurring in the centralportion thereof increases the deformation amount.

For example, in a case where the flange portions 613 and 623 of the leftand right side frames 61 and 61 and the left and right middle frames 62and 62 are joined over the entire length and there is no non-jointportion n, great deformation can be generated in the central portion.

In contrast, in a case where the non-joint portion n is provided on theleft and right side frames 61 and 61 and the left and right middleframes 62 and 62, it is possible to guide the deformation position tothe non-joint portion n where the joining strength is low. Inparticular, since the non-joint portion n of each of the left and rightside frames 61 and 61 and the left and right middle frames 62 and 62 islocated on the lower side which is one side with respect to the centralportion in the up-down direction, it is possible to avoid deformation ofthe central portion.

This makes it possible to generate deformation at the side below thecentral portion where large deformation is likely to occur and thus,reduce the deformation amount and the deflection amount.

Moreover, since the non-joint portions n of the outer side frames 61 and61 are positioned slightly higher than the non-joint portions n of themiddle frames 62 and 62 on the central portion, the non-joint portions nof the frames 61, 61, 62, and 62 are arranged in a range roughly alongthe arc about the central portion of the skeletal structure 100 as acenter, it is possible to easily generate deformation along the arc, andit is possible to suppress the deformation of the central portion in acase where a load is applied to the central portion of the skeletalstructure 100, and instead possible to deform the surrounding portion,leading to further effective reduction of the deformation amount and thedeflection amount.

While the above describes a more preferable example in which thenon-joint portions n of the individual frames 61, 61, 62, and 62 arearranged approximately along the arc about the central portion of theskeletal structure 100 as a center, it is still possible to reduce thedeformation amount and the deflection amount even in a case wherenon-joint portions n of the individual frames 61, 61, 62, and 62 arealigned at the same height.

Moreover, the overlapping range j of the non-joint portion n of the sideframes 61 and 61 and the non-joint portion n of the middle frames 62 and62 are arranged to include boundaries between adjacent sections withrespect to a portion of the reinforcing structure sections 30A through30D, 50A, and 50B formed in each of the regions A to C of the panel 1described above.

That is, in the case of the region A, the boundary between the thirdsection 30B from the bottom and the second section 30A from the bottomand the boundary between the second section 30A from the bottom and thelowermost section 30C are inside the overlapping range j in the up-downdirection.

Moreover, in the case of the region B, the boundary between the thirdsection 30B from the bottom and the second section 30A from the bottomand the boundary between the second section 30A from the bottom and thelowermost section 30D are inside the overlapping range j in the up-downdirection.

Moreover, in the case of the region C, the boundary between the thirdsection 50B from the bottom and the second section 50B from the bottomand the boundary between the second section 50B from the bottom and thelowermost section 50B are inside the overlapping range j in the up-downdirection.

The boundary between the sections of the reinforcing structure tends tobe deformed along the boundary as compared with the other portions.Accordingly, by including the boundary between the sections within theoverlapping range j in the up-down direction as described above, it ispossible to more effectively guide the deformation position to the lowerside than the central portion and to more effectively reduce thedeformation amount and the deflection amount.

While this is a case where the boundary between the two sectionsarranged in the up-down direction is included in the overlapping rangej, the number may be one, or three or more.

[Joint Structure of Individual Frames]

FIG. 8 is a front view of the joint between the upper frame 63 and themiddle frame 62. FIG. 9 is a perspective view as viewed diagonally fromthe front upper side. FIG. 10 is a perspective view of the cross sectiontaken along line X-X of FIG. 8 viewed diagonally from the left frontupper side. FIG. 11 is a perspective view of the cross section takenalong line Y-Y of FIG. 8 as viewed diagonally from the right front upperside.

The joint structure between the frames will be described with referenceto FIGS. 5, 6, and 8 to 11 .

The upper end portion of the middle frame 62 is formed into notches 624and 624 by removing the flange portions 623 and 623 on both sides andcutting off a pair of side walls 622 and 622 up to the vicinity of anopposing wall 621. Due to the notches 624 and 624, the upper end portionof the middle frame 62 includes merely the opposing wall 621 and theslightly-left side wall 622.

In joining the upper frame 63 to the middle frame 62, the upper frame 63enters the notches 624 and 624.

In a state where the upper frame 63 and the middle frame 62 are joinedwith each other, the notches 624 and 624 have such a shape that a gap isgenerated with respect to the lower side wall 632 of the upper frame 63(refer to FIGS. 6 and 10 ). With this configuration, when a load isapplied to the skeletal structure 100, it is possible to effectivelyavoid the generation of abnormal noise caused by the rubbing between theedges of the notches 624 and 624 and the lower side wall 632 of theupper frame 63. Moreover, this gap makes it possible to absorbassembling errors and processing errors of the upper frame 63 and themiddle frame 62, and to easily perform assembly and joining operation.

Furthermore, at the upper end portion of the opposing wall 621 of themiddle frame 62, an irregular structure 625 in which the front surfaceof the opposing wall is recessed rearward in a U shape is formed so asto protrude toward the panel 1 side.

As illustrated in FIGS. 9 and 10 , due to the formation of the irregularstructure 625, the opposing wall 621 of the upper end portion of themiddle frame 62 is recessed at its central portion, protruding rearward,with its tip end portion being formed into a flat shape. The flatsurface at the tip end is joined by laser welding in a state of being insurface contact with the front surface of the opposing wall 631 of theupper frame 63.

Both the left and right sides of the recess in the central portion ofthe irregular structure 625 are relatively protruding forward and have aridge-shape along the up-down direction.

Furthermore, the irregular structure 625 extends downward from the upperend portion of the middle frame 62 to a length approximately equal to orgreater than the vertical width of the opposing wall 631 of the upperframe 63.

Since the upper end portion of the middle frame 62 has most of the pairof side walls 622 being removed by the notch 624, the strength in theupper end portion of the middle frame 62 against the load in thefront-rear direction by the pair of side walls 622 is reduced ascompared to the case without the notches.

Still, since the upper end portion of the middle frame 62 includes theridges formed along the up-down direction by the irregular structure 625on the left and right sides, it is possible to enhance the rigidity ofthe upper end portion of the middle frame 62 to achieve sufficientstrength against the load in the front-rear direction.

Moreover, the lower side of the irregular structure 625 in the opposingwall 621 of the middle frame 62 includes an inclined surface 626inclined in a direction in which the opposing wall 621 separates awayfrom the panel 1 in an upward direction.

Due to this inclined surface 626, the width of the pair of side walls622 in the front-rear direction is wider than the lower portion in thevicinity of the upper end portion of the middle frame 62. With thisconfiguration, even when the notches 624 are formed in the pair of sidewalls 622, the side walls 622 are not completely removed, making itpossible to ensure the strength of the upper end portion of the middleframe 62.

In addition, in the middle frame 62, the upper end portions of theflange portions 623 and 623 overlap with the lower flange portion 633 ofthe upper frame 63 on the lower side of the notches 624 and 624 andjoined with each other by laser welding. This further enhances thejoining strength between the middle frame 62 and the upper frame 63.

As described above, the upper frame 63 is joined to the inside of thegroove-like recess 21 recessed rearward on the front surface of thepanel 1. Since the depth of the recess 21 matches the thickness of theflange portion 633 of the upper frame 63, the flange portion 623 of themiddle frame 62 has no gap with respect to the front surface of thepanel 1 even when the flange portion 623 of the middle frame 62 isoverlapped and joined in front of the flange portion 633 of the upperframe 63. This makes it possible to satisfactorily join the flangeportion 623 of the middle frame 62 to the front surface of the panel 1by laser welding.

As illustrated in FIGS. 1 and 2 , the lower end portion of the middleframe 62 has the same structure as the structures of the notchedportions 624 and 624, the irregular structure 625, and the inclinedsurface 626 at the upper end portion, and is joined to the lower frame64.

Furthermore, the upper end portion of the side frame 61 has the samestructure as the structure of the notched portions 624 and 624, theirregular structure 625, and the inclined surface 626 at the upper endportion of the middle frame 62 and is joined to the upper frame 63,while the lower end portion of the side frame 61 is joined to the lowerframe 64 by a structure different from the structure of the middle frame62.

The lower end portions of the left and right side frames 61 are joinedto the left and right end portions of the lower frame 64. There is aneed to provide a projection nut to be used in attaching the skeletalstructure 100 to the seat frame at the lower corner of the skeletalstructure 100, which is the joining position. Therefore, in order toavoid interference, it is difficult to extend the lower end portions ofthe left and right side frames 61 and the left and right end portions ofthe lower frame 64 to the lower corner of the skeletal structure 100.

Accordingly, the lower end portion of the left-side side frame 61 iscoupled to the left end portion of the lower frame 64 via the plate-likeset bracket 16A including the projection nut 161. The lower end portionof the right-side side frame 61 is coupled to the right end portion ofthe lower frame 64 via a plate-like set bracket 16B including theprojection nut 161.

As illustrated in FIGS. 1 and 2 , the set bracket 16A is an L-shapedmetal plate in front view, and is joined to the left end portion of therecess 22 on the front surface of the panel 1 by laser welding.

In the set bracket 16A, the projection nut 161 is fixedly mounted byprojection welding onto the front surface of a corner of the L-shape. Abolt to fix the skeletal structure 100 to the vehicle seat can bescrewed into the projection nut 161 via a through hole (not illustrated)provided in the lower corner of the panel 1.

Moreover, in the set bracket 16A, the lower end portion of the flangeportion of the left-side side frame 61 is joined to the front surface ofan extension extending upward from the corner by laser welding.

Furthermore, in the set bracket 16A, the left end portion of the flangeportion of the lower frame 64 is joined to the front surface of anextension extending rightward from the corner by laser welding.

With this configuration, the set bracket 16A couples the lower endportion of the left-side side frame 61 and the left end portion of thelower frame 64.

Moreover, a flange portion rising frontward is formed from the left edgeof the extension extending above the set bracket 16A to the lower edgeof the extension extending rightward, and a flange portion risingfrontward is formed from the right edge of the extension extending abovethe set bracket 16A to the upper edge of the extension extendingrightward. These constitute a reinforcing structure of the set bracket16A to reduce deflection and deformation against the load of the setbracket 16A.

Moreover, the set bracket 16B has a structure symmetrical with the setbracket 16A, and thus, a detailed description thereof will be omitted.Similarly to the set bracket 16A, the set bracket 16B couples the lowerend portion of the right-side side frame 61 and the right end portion ofthe lower frame 64.

Since the projection nut 161 is joined by projection welding, it isdifficult to directly join the projection nut 161 to the thin panel 1.That is, it is difficult to attach the projection nut 161 to the panel 1without using the set brackets 16A and 16B thicker than the panel 1.

Since the right and left side frames 61 and 61 are coupled with thelower frame 64 using these indispensable set brackets 16A and 16B, it ispossible to couple the left and right side frames 61 and 61 with thelower frame 64 without interfering with the projection nut 161.

In addition, the set brackets 16A and 16B have high rigidity becausethey are thicker than the panel 1 and include the flange portions.Accordingly, even when the left and right side frames 61 and 61 arecoupled with the lower frame 64 via the set brackets 16A and 16B, it isstill possible to maintain sufficiently high coupling strength betweeneach other.

[Other Members]

As illustrated in FIGS. 1 and 2 , the support member 12 of the headrestis joined to the upper frame 63 by welding, in one pair for each of theregions A, B, and C of the panel 1 described above. Each of the supportmembers 12 has a square tubular shape and is attached along the up-downdirection. The headrest is supported in a state where a support columnof the headrest is inserted into the inside of the support member 12from above.

The striker 11 is a metal fitting for fixing the backrest of the rearseat and the skeletal structure 100 to the vehicle body. The lower endportion of the frame 6 is fixed by the above-described two projectionnuts 161 and 161, while at the upper end portion of the frame 6, thestriker 11 is locked to a fastener provided on the vehicle body.

The striker 11 is formed by bending a single thick metal wire material.Both end portions of the wire material are joined to the opposing wall631 by laser welding at the middle portion of the upper frame 63 in thelongitudinal direction, and an intermediate portion of the wire materialis folded rearward from the upper end portion of the panel 1, furtherbent into a hook shape extending downward.

The pair of armrest brackets 13 and 14 is a member that rotatablysupports the armrest equipped on the vehicle seat.

FIG. 12 is a perspective view illustrating a portion of the left-sidearmrest bracket 13 in a vertical section. FIG. 13 is a perspective viewillustrating a portion of the left-side armrest bracket 13 in ahorizontal section.

The armrest bracket 13 includes a base end portion 131 joined to thefront surface of the opposing wall 641 of the lower frame 64, a supportarm 132 extending diagonally upward and forward from the base endportion 131, a bead 133 to reinforce the support arm 132, and a flangeportion 134 formed along outer edges of the base end portion 131 and thesupport arm 132. These portions are formed from a single metal plate bypressing.

The base end portion 131 and the support arm 132 have side walls risingfrom the outer periphery thereof, and the above-described flange portion134 protrudes outward at the tip end portion of the side wall.

In addition, the tip end portion of the support arm 132 includes athrough hole formed to allow a support shaft that supports the armrestto pass through. Furthermore, the bead 133 bulging rightward from theend portion on the base end portion 131 side toward the extending endside is formed on the support arm 132. The rigidity of the armrestbracket 13 is enhanced by the side wall, the bead 133, and the flangeportion 134, ensuring sufficient supporting strength of the armrest.

Moreover, the base end portion 131 is joined to the front surface of theopposing wall 641 of the lower frame 64 by laser welding. While joiningthe armrest bracket 13 would be difficult by the welding methods otherthan laser welding in a narrow region such as the opposing wall part 641of the lower frame 64, the laser welding makes it possible to performjoining by laser emission from the rear. Therefore, the laser weldingenables the armrest bracket 13 to be provided at a proper position withsufficient strength.

As illustrated in FIGS. 1 and 2 , the right-side armrest bracket 14includes a base end portion joined to the front surface of the opposingwall 621 of the middle frame 62, a support arm extending forward fromthe base end portion, and a flange portion formed along outer edges ofthe base end portion and the support arm. These portions are formed froma single metal plate by pressing.

Since the right-side armrest bracket 14 is joined to the middle frame62, there is no need to extend the support arm unlike the case of theleft-side armrest bracket 13, sufficient strength is obtained withoutproviding the bead.

The base end portion of the armrest bracket 14 is also joined to themiddle frame 62 by laser welding.

[Technical Effect of Embodiment of Invention]

As described above, the plurality of reinforcing structure sectionssurrounded by the beads bulging from the panel 1 into ridge shapes isformed in each of the regions A to C of the panel 1 of the skeletalstructure 100.

By surrounding with beads along each of the up-down, left-rightdirections like the reinforcing structure sections 30A to 30D, 50A and50B, the individual beads can increase the rigidity against the loadfrom different directions, making it possible to suppress deformation ofthe panel 1 due to the load from more versatile directions. Moreover,since the beads having different directions are connected to each otheruninterruptedly to surround each of the sections, it is possible tosuppress the reduction in rigidity that might occur in separated portioncaused by arranging the beads spaced apart from each other. Thisconfiguration makes it possible to reduce the deflection in a pluralityof directions in the region surrounded by the beads.

Furthermore, since the plurality reinforcing structure sectionssurrounded by the beads is provided in each of the regions A to C, it ispossible to receive the load applied to the skeletal structure 100 foreach of the sections and suppress the overall deformation.

In addition, arranging the plurality of sections makes it possible toreduce the planar deflection and elastic deformation of the panel,leading to the reduction of the occurrence of abnormal noise due toreturn from the deformed state.

Moreover, the reinforcing structure sections 30A to 30D, 50A and 50Bsurrounded by the beads are further divided into subsections by theauxiliary beads, making it possible to further enhance the rigidity anddistribute the stress, leading to further reduction of the deflectionand elastic deformation.

The reinforcing structure sections 30A to 30D in particular includesubsections divided into truss shapes such as a triangle shape by theauxiliary beads. The subsection having truss shape such as a trianglecan decrease the number of portions having a long distance between thebead (or auxiliary bead) and the bead (or auxiliary bead) as comparedwith hexagonal reinforcing structure subsections, for example, ahoneycomb structure. Accordingly, this makes it possible to furtherreduce deflection and elastic deformation within the subsection.

Moreover, the regions A and B have arrangements such as the reinforcingstructure sections 30A and 30B, so as to allow the formation patterns ofthe auxiliary beads in the adjacent sections to be line-symmetricalabout the boundary line as a center. For example, arranging sectionshaving the same-shaped patterns in the same direction might causeweakness in each of the sections against the load from the samedirection and might be likely to generate deflection in the samedirection. In contrast, by arranging the auxiliary beads within theadjacent sections into line-symmetrical formation pattern, it ispossible to avoid a likelihood of generation of deflection in the samedirection since the directions of loads likely to generate deflection donot match section by section. Accordingly, it is possible to reducedeflection and elastic deformation against the load from more versatiledirections.

Moreover, in each of the regions A to C, the plurality of reinforcingstructure sections is arranged in the up-down direction to be formed onthe panel 1, and additionally, the side frame 61 or the middle frame 62joined to the panel 1 is arranged on both sides of each of the regions,along the up-down direction.

With this configuration, the deflection of the plurality of sectionsaligned in the up-down direction that might occur along the boundaryline can be suppressed by the side frames 61 or the middle frame 62 onadjacent sides, making it possible to reduce the deflection and elasticdeformation of the entire panel 1.

Furthermore, the upper end portion and the lower end portion of each ofthe side frame 61 and the middle frame 62 are respectively joined to theupper frame 63 and the lower frame 64 provided along the left-rightdirection. With this configuration, each of the side frame 61 and themiddle frame 62 can maintain its orientation and position, making itpossible to further reduce deflection and elastic deformation of theentire panel 1.

In the skeletal structure 100, the panel 1 and each of the frames 61 to64 are joined to each other by laser welding at mutual joint surfaces ofthe panels 1 and the frames 61 to 64 by the solidified state aftermelting generated in the material for forming the panel 1 and thematerial for forming the frames 61 to 64. Accordingly, joining isachieved without adding a welding material other than the panel 1 andeach of the frames 61 to 64, leading to the reduction of the weight ofthe skeletal structure 100 while maintaining high joining strength.

Moreover, since laser welding is performed as a method for manufacturingthe skeletal structure, in which the panel 1 and each of the frames 61to 64 are melted to be joined by solidification thereafter, it ispossible to achieve welding in a range wider as compared with the caseof conventional spot welding, or the like, leading to enhancedproductivity.

Moreover, in the skeletal structure 100, each of the frames 61 to 64 ofthe frame 6 has an open cross-sectional shape and the end portions ofthe side frames 61 and the middle frames 62 are joined in a state ofbeing overlapped with the upper frame 63 or the lower frame 64. Thismakes it easy to ensure a wide area of the joint, leading to theenhanced joining strength.

Moreover, the side frame 61 or the middle frame 62 of the skeletalstructure 100 includes a notch at the upper end portion or the lower endportion, and the panel-side opposing surface of the opposing wall isjoined to the upper frame 63 or the lower frame 64 arranged inside thenotch. This configuration makes it possible to obtain the wider area ofthe joint so as to further enhance the joining strength.

Moreover, since the notch of the side frame 61 or the middle frame 62has a gap with respect to the side wall of the upper frame 63 or thelower frame 64, it is possible to suppress the occurrence of abnormalnoise due to sliding operation with the side wall. In addition, due tothe presence of the gap, it is possible to allow processing errors,assembly errors, and thermal deformation of the side frame 61 or themiddle frame 62.

Moreover, in the side frame 61 or the middle frame 62 of the skeletalstructure 100, the opposing wall at the upper end portion or the lowerend portion includes the irregular structure 625 having a protrusion atthe center relative to the panel 1. This configuration can increase therigidity of the irregular structure 625 against the load in thedirection facing the opposing wall, leading to the enhanced strength atthe joint between the frames.

In addition, in the side frame 61 or the middle frame 62 of the skeletalstructure 100, the inclined surface 626 separated away from the panel 1toward the tip end of the frame is formed in the opposing wall 621. Withthis configuration, it is possible to ensure a wide width of the sidewall 622 on the end portion on which the notch 624 is formed, andpossible to maintain the strength of the joining end portion of the sideframe 61 or the middle frame 62 high.

Moreover, joining is performed in a state where the tip end portion ofthe flange portion of the side frame 61 or the middle frame 62 of theskeletal structure 100 overlaps with a portion of the flange portion ofthe upper frame 63 or the lower frame 64. This brings the side frame 61or the middle frame 62 into a state of being joined with the upper frame63 or the lower frame 64 by both the opposing wall and the flangeportion, making it possible to further enhance the joining strength.

In addition, in the left and right side frames 61 and the left and rightmiddle frames 62 of the skeletal structure 100, the non-joint portions ntoward the panel 1 are arranged to overlap each other in the overlappingrange j in the up-down direction. This makes it possible to controldeformation to be generated in the overlapping range j in a case wherethe skeletal structure receives a collision load or a deformation load.

In particular, by arranging the overlapping range j to be lower than thecentral portion in the up-down direction of the panel, it is possible togenerate deformation in a portion other than the central portion that islikely to develop a great amount of deformation at the time ofoccurrence of deformation, leading to reduction of the deformationamount.

Note that the overlapping range j is not limited to the side lower thanthe central portion and may be in the upper side as long as it ispossible to suppress the occurrence of deformation in the centralportion of the panel 1 that is likely to develop a great amount ofdeformation.

Moreover, the left and right side frames 61 and 61 of the skeletalstructure 100 are arranged such that the non-joint portion n is closerto the central portion (upper) in the up-down direction than thenon-joint portions n of the left and right middle frames 62 and 62. Thisleads to the state of the non-joint portions n of the frames 61, 61, 62and 62 being arranged along the arc about the center of the panel as acenter. Accordingly, even when a collision load or a deformation load isapplied to the center of the panel, it is possible to generatedeformation along the arc along which the non-joint portions n arearranged, and possible to guide the deformation position moreeffectively and to reduce the deformation amount.

Moreover, the overlapping range j of the non-joint portion n in the leftand right side frames 61 and the left and right middle frames 62 of theskeletal structure 100 is defined as a range including one or more (forexample, two) positions to be a boundary between the reinforcingstructure sections arranged vertically in the panel 1, with respect tothe up-down direction. This leads to a state that includes a boundaryline between the mutual sections where deformation is likely to occur,making it possible to control the deformation position furthereffectively and reduce the deformation amount.

In addition, since the left and right side frames 61 of the skeletalstructure 100 are coupled to the lower frame 64 using the set brackets16A and 16B which are indispensable for attaching the projection nut 161to the panel 1, it is possible to couple the left and right side frames61 and 61 to the lower frame 64 without interfering with the projectionnuts 161.

Second Embodiment

As a second embodiment, a skeletal structure 100F of a vehicle seat asanother example will be described. The skeletal structure 100F of thevehicle seat will be described mainly in terms of differences from theskeletal structure 100 described above, and the same reference numeralsas those of the skeletal structure 100 are used for the sameconfiguration, and redundant description will be omitted.

In the following, while various technically preferable limitations forimplementing the present invention are attached to the followingembodiments, the scope of the present invention is not limited to thefollowing embodiments and illustrative examples.

FIG. 14 is a front view of the skeletal structure 100F of the vehicleseat. FIG. 15 is an enlarged perspective view of an upper centralportion of the skeletal structure 100F. FIG. 16 is an enlargedperspective view of a lower left portion thereof.

The skeletal structure 100F is attached to the vehicle in a same manneras the skeletal structure 100. Moreover, in a state where the skeletalstructure 100F is mounted on the vehicle seat, the left side of thevehicle is defined as the left side of the skeletal structure 100F andthe right side of the vehicle is defined as the right side of theskeletal structure 100F. In FIG. 14 , the front side of the page isdefined as the “front” and the back side of the page is defined as the“rear”.

The skeletal structure 100F includes a panel 1F, the frame 6, thestriker 11, the plurality of headrest support members 12, headrestpillars 17F and 17G, a pair of armrest brackets 13 and 13F.

Similarly to the panel 1, the panel 1F has a substantially rectangularshape and is a metal plate formed of steel, an aluminum alloy, or thelike.

Similarly to the panel 1, the panel (pan frame) 1F is divided into threeregions A to C by the left and right side frames 61 and 61 and the leftand right middle frames 62 and 62.

The left region A of the panel 1 includes reinforcing structure sections30F, 30G, 30H, 30G, 30H, 30G, 30I, 30J sequentially formed in order fromthe top.

The reinforcing structure section 30G includes a substantiallyrectangular bead surrounding the section 30G and two auxiliary beadsdividing the section 30G surrounded by the bead into three subsections.

That is, the bead is a rectangle with a rounded corner.

The auxiliary bead is formed across the diagonal upper left and thediagonal lower left in the inner region of the bead.

This results in formation of an isosceles trapezoidal-shaped subsectionat the center of the rectangular inner region of the bead, andbilaterally symmetrical formation of trapezoidal subsections each havingunequal legs and two right-angled corners.

The reinforcing structure section 30H has a pattern shape beingvertically inverted pattern shape of the section 30G. That is, the shapeis a line-symmetrical pattern shape with respect to the section 30Gabout an axis along the left-right direction as a center.

The reinforcing structure section 30I has a pattern shape substantiallyequal to the section 30H except that the shape lacks a portion of thelower left portion in order to avoid interference with a set bracket 16Fdescribed below.

The reinforcing structure section 30F includes a substantiallyrectangular bead surrounding the section 30F and an auxiliary beadforming three rectangular subsections within the section 30F surroundedby the bead.

That is, the bead is a rectangle with a rounded corner similarly to thesection 30G.

The auxiliary bead is a rounded rectangle smaller than the section 30G,and three auxiliary beads are formed in the left-right direction. Inaddition, each of the subsections includes a substantially trapezoidalopening.

The reinforcing structure section 30J includes a substantiallytrapezoidal bead surrounding the section 30J and an auxiliary beaddividing the section 30J surrounded by the bead into two subsections.

That is, the bead is formed in a trapezoidal shape with the cornersrounded, having unequal legs and two right-angled corners at the rightside. In addition, the left side of the bead is shaped to avoidinterference with the set bracket 16F.

The auxiliary bead is formed diagonally over the upper left in the innerregion of the bead.

This results in formation of a trapezoidal subsection having unequallegs and two right-angled corners on the right side of the inner regionof the bead, and formation of a subsection of parallelogram on the leftside of the inner region of the bead.

As illustrated in FIG. 14 , the right region B of the panel 1F includesthe reinforcing structure sections 30F, 30G, 30H, 30G, 30H, 30G, 30K,and 30L sequentially formed in order from the top.

This right region B has a horizontally inverted shape of the entireregion A, that is, a line-symmetrical pattern shape with respect to eachof the sections 30F to 30J of the region A about an axis along theup-down direction as a center. Therefore, a detailed description thereofwill be omitted.

The central region C of the panel 1F includes reinforcing structuresections 30M, 30N, 30O, 30N, 30O, 30N, and 30P sequentially formed inorder from the top.

The reinforcing structure section 30M is shaped substantially equally tothe above-described section 30F, including a beads formation patterngenerally reduced from the section 30F in the left-right direction.

The reinforcing structure section 30N is shaped substantially equally tothe above-described section 30H, including a beads formation patterngenerally reduced from the section 30H in the left-right direction.

The reinforcing structure section 30O is shaped substantially equally tothe above-described section 30G, including a beads formation patterngenerally reduced from the section 30G in the left-right direction.

The reinforcing structure section 30P includes a substantiallyrectangular bead surrounding the section 30P and two auxiliary beadsfurther dividing the section 30P surrounded by the bead into threesubsections.

That is, the bead is a rectangle with a rounded corner.

The auxiliary bead is formed across the diagonal upper left and thediagonal lower left in the inner region of the bead.

This results in formation of an isosceles trapezoidal-shaped subsectionat the center of the rectangular inner region of the bead, andsymmetrical formation of trapezoidal subsections each having unequallegs and two right-angled corners provided on the left and right sides.In addition, the isosceles trapezoidal-shaped subsection is shaped toinclude a downward recess in the central portion.

Each of all the reinforcing structure sections of each of the regions Ato C includes a circular through hole 46F penetrating the panel 1F inthe front-rear direction in each of the inner subsections, except forthe sections 30F and 30M. In addition, a circular protrusion concentricwith the through hole 46F and having a large diameter protrudes forwardin the periphery of each of the through holes 46F. That is, weightreduction is aimed by forming the through hole 46F in almost all thesub-regions, higher rigidity is aimed by forming the irregular structureby protrusions, so as to suppress the strength reduction due toformation of the through holes 46F.

Moreover, a portion of the through holes 46F provided at specifiedpositions (for example, any of the four corners of the panel 1F) is usedfor positioning the panel 1F with respect to a laser welding apparatus.

As illustrated in FIGS. 14 and 16 , a right-side set bracket 16G is ametal plate having a substantially triangular shape in front view, andis joined to the lower right end portion of the front surface of thepanel 1F by laser welding.

In this set bracket 16G, a projection nut 161 is fixedly mounted byprojection welding onto the front surface of a right angle corner.

Moreover, in the set bracket 16G, the lower end portion of the flangeportion of the right-side side frame 61 is joined to the upper portionof the right-angled corner by laser welding, and the right end portionof the flange portion of the lower frame 64 is joined to the leftportion of the right-angled corner by laser welding. With thisconfiguration, the set bracket 16G couples the lower end portion of theright-side side frame 61 and the right end portion of the lower frame64.

The set bracket 16G includes a substantially triangular irregularstructure protruding rearward formed in a region between the right-sideside frame 61 and the lower frame 64, so as to enhance the rigidity.

Furthermore, the set bracket 16G includes an extension 162 extendingfrom the substantially triangular irregular structure toward the centerside of the panel 1F, and the tip end portion of the extension 162 isjoined to the lower right portion of the front surface of the panel 1Fby laser welding.

A reinforcing structure in a ridge shape that protrudes forward isformed along the diagonally lower left side in the vicinity of the tipend portion of the extension 162.

The shape and structure of the left-side set bracket 16F corresponds toa shape obtained by horizontally inverting the set bracket 16G. That is,since the left-side set bracket 16F has a shape and structuresymmetrical with respect to the set bracket 16G about a plane along theup-down and front-rear directions as a center, the detailed descriptionthereof will be omitted.

These set brackets 16F and 16G have rigidity equal to or higher thanthat of the set brackets 16A and 16B described above due to thereinforcing structure. Furthermore, the set brackets 16F and 16G arejoined to the panel 1F by laser welding at the tip end of the extension162, leading to enhanced mutual joining strength compared with the setbrackets 16A and 16B.

The headrest pillar 17F is mounted on each of the support members 12 ofthe pair of headrests in the left region A and the right region B. Theheadrest pillar 17F is formed by bending a single thick metal wirematerial. Both end portions of the wire material are inserted from theupper end portion of the support member 12 of the pair of headrests soas to be joined by welding, and an intermediate portion of the wirematerial is folded frontward from the upper end portion of the panel 1F,further folded downward to be bent into a hook shape as a whole.

A reinforcing wire 171F is joined to the intermediate portion of thewire material of the headrest pillar 17F, that is, the portioncorresponding to the tip end of the hook bent downward by welding so asto be arranged across the wire materials.

Moreover, the headrest pillar 17G is mounted on the pair of headrestsupport members 12 in the central region C. The headrest pillar 17G isobtained by bending a single thick metal wire material. Both endportions of the wire material are inserted from the upper end portion ofthe support member 12 of the pair of headrests to be joined by welding,and an intermediate portion of the wire material is folded frontwardfrom the upper end portion of the panel 1F, further folded diagonallydownward to be bent into a gentle angled hook shape as a whole by theheadrest pillar 17F.

A reinforcing wire 171G is also joined to the intermediate portion ofthe wire material of the headrest pillar 17G by welding.

In addition, a backboard engaging wire 172G formed of a wire materialbent into a rectangular frame shape is fixedly mounted onto the frontsurface of the panel 1F by welding under the headrest pillar 17G.

A plate-like backboard is arranged on the front surface side of thecentral region C of the panel 1F when the skeletal structure 100F isattached to the rear seat, and the upper end portion of the backboard isinserted into a backboard engaging wire 172G. The upper end portion ofthe backboard includes a claw extending forward.

In a case where a collision from the rear, etc. occurs and this appliesa forward load or stress to the lower center portion of the skeletalstructure 100F to be deformed forward, the backboard is also pushedforward. In this case, however, the claw at the upper end portion iscaught by the backboard engaging wire 172G to prevent extrusion, makingit possible to suppress forward deformation of the skeletal structure100F.

The pair of armrest brackets 13 and 13F is fixedly mounted onto thelower frame 64 by laser welding.

In this skeletal structure 100F, the armrest bracket 13F is providedinstead of the right-side armrest bracket 14 described above.

The armrest bracket 13F has a shape obtained by horizontally invertingthe armrest bracket 13. That is, since the armrest bracket 13F has ashape and structure which is plane-symmetrical with respect to thearmrest bracket 13 about a plane along the up-down and front-reardirections, the detailed description thereof will be omitted.

The skeletal structure 100F is applicable to obtain the same technicaleffect as the skeletal structure 100 described above and additionallyhas excellent enhancement such as enhanced productivity by simplifiedpatterns of the reinforcing structure beads in the panel 1F, the weightreduction due to the through holes 46F formed in each of the reinforcingstructure sub-regions, and enhanced rigidity due to the use of theheadrest pillars 17F and 17G, the pair of armrest brackets 13 and 13F,and the set brackets 16F and 16G.

[Others]

The layout of the plurality of regions including the reinforcingstructure sections of the panels 1 and 1F is not limited to thatillustrated in FIG. 1 or FIG. 14 . For example, each of the regions maybe decreased or increased.

In addition, in the case of using the skeletal structures 100 and 100Ffor the backrest of the rear seat, there may be a case of adopting astructure capable of inserting luggage from a rear-side loading platformby opening the central portion of the backrest.

In order to manage this, it is also allowable to change the entirereinforcing structure formation zone in the region B in the skeletalstructures 100 and 100F into a wide opening portion.

Moreover, while the side frame 61, the middle frame 62, the upper frame63, and the lower frame 64 constituting the frame 6 are all providedwith flange portions, it is also allowable to adopt a configuration inwhich the panel-side end surface of the side wall is used for joiningwithout providing the flange portions.

INDUSTRIAL APPLICABILITY

The present invention is applicable in the field of a skeletal structurethat joins a frame and a panel.

EXPLANATION OF REFERENCE NUMERALS

-   -   1, 1F panel    -   6 frame    -   11 striker    -   12 support member    -   13, 13F, 14 armrest bracket    -   16A, 16B, 16F, 16G set bracket    -   21, 22 recess    -   30A to 30P, 50A, 50B reinforcing structure section    -   31 to 34 bead    -   35 to 39 auxiliary bead    -   41 to 45 subsection    -   46 to 49, 46F through hole    -   61 side frame (first frame)    -   62 middle frame (first frame)    -   63 upper frame (second frame)    -   64 lower frame (second frame)    -   100, 100F skeletal structure    -   131 base end portion    -   132 support arm    -   133 bead    -   134 flange portion    -   161 projection nut    -   613, 623 flange portion    -   621 opposing wall    -   622 side wall    -   623 flange portion    -   624 notch    -   625 irregular structure    -   626 inclined surface    -   631 opposing wall    -   632 side wall    -   633 flange portion    -   641 opposing wall    -   A left region    -   B right region    -   C central region    -   j overlapping range    -   n non-joint portion    -   s joint portion

The invention claimed is:
 1. A skeletal structure comprising: a panel; aframe joined to a front surface side of the panel, the frame including aplurality of first frames oriented in a fixed direction and a secondframe oriented in a direction orthogonal to the plurality of firstframes, each of the plurality of first frames and the second frame isformed to have an open cross-sectional shape, wherein: an end portion ofeach first frame of the plurality of first frames is joined to thesecond frame in an overlapping state, each of the plurality of firstframes and the second frame includes an opposing wall facing the paneland a pair of side walls extending from both side portions of theopposing wall toward the panel, and a panel-side opposing surface of theopposing wall of each first frame of the plurality of first frames isjoined to the second frame that is arranged inside a notch formed in thepair of side walls at the end portion of each first frame.
 2. Theskeletal structure according to claim 1, wherein the opposing wall atthe end portion of each first frame of the plurality of first framesincludes an irregular structure that has, at a center, a protrusionprotruding toward the panel.
 3. The skeletal structure according toclaim 1, wherein the opposing wall at the end portion of each firstframe of the plurality of first frames includes an inclined surface thatis inclined to be farther away from the panel as the inclined surface iscloser to a tip end of each first frame of the plurality of firstframes.
 4. The skeletal structure according to claim 1, wherein thenotch in the pair of side walls of each first frame of the plurality offirst frames has a gap with respect to a side wall among the side wallsof the second frame.
 5. The skeletal structure according to claim 1,wherein: each first frame of the plurality of first frames and thesecond frame includes flange portions that are formed at panel-side endportions of the side walls, and a part of the flange portions of eachfirst frame of the plurality of first frames and a part of the flangeportions of the second frame are joined to each other in an overlappingstate.
 6. The skeletal structure according to claim 1, wherein the paneland the frame are welded to each other on mutual joint surfaces.
 7. Amethod of manufacturing a skeletal structure, the method comprisingjoining: (i) a frame to a front surface side of a panel, the frameincluding a plurality of first frames oriented in a fixed direction anda second frame oriented in a direction orthogonal to the plurality offirst frames, each of the plurality of first frames and the second frameare formed to have an open cross-sectional shape, and (ii) an endportion of each first frame of the plurality of first frames is joinedto the second frame in an overlapping state, each of the plurality offirst frames and the second frame includes an opposing wall facing thepanel and a pair of side walls extending from both side portions of theopposing wall toward the panel, and a panel-side opposing surface of theopposing wall of each first frame of the plurality of first frames isjoined to the second frame that is arranged inside a notch formed in thepair of side walls at the end portion of each first frame.